Is there a way to make a script that enables buttons if a player has a specific item by click?

Also if they don't how would I enable a GUI? I tried thing like: clickdetector.MouseClick:connect(onMouseClick)

local Tool = player.Backpack:FindFirstChild("ButtonKey") or player.Character:FindFirstChild("ButtonKey")

game.Workspace.ButtonKeyEvent.OnServerEvent:Connect(function()

Just lots of stuff please help me out and tell me how it would work in a nice simple way.